Vestibular and Neck Contribution to Oculomotor Processing in the Frontal Cortex

描述(申请人提供)：过去的大量研究表明，诱发的眼动向量反映了视觉运动坐标转换的过程。最近的一些研究表明，前庭和/或颈部本体感觉等非动眼变量可以改变动眼坐标。我们的初步研究进一步表明，随着静态垂直头部位置的改变，额叶眼场(FEF)中神经诱发的扫视向量的方向发生了补偿方向的移动。这些发现共同表明，即使头部不动，前庭和/或颈部的输入在更新视觉运动坐标系中可能也是关键的。基于这些发现，我们假设耳石，即内耳器官，专门用于检测相对于重力的静态头部位置，可能为额叶皮质提供关键的输入，以帮助形成动眼坐标。或者，颈部本体感觉输入通常与前庭信号一起变化，可能是重要的。为了确定我们的结果是否仅由前庭输入(前庭假说)、颈部本体感觉输入(颈部假说)或两者共同贡献，我们开发了一种新的方法，该方法允许基于对相关运动变量的独立控制来分离前庭和颈部的影响，例如，头自由动物的初始眼部位置(IEP)、初始头部位置(IHP)和初始颈部位置(INP)。在拟议的实验中，将通过对这些变量的系统操作来评估工作假设的预测。在具体目标1下，我们将评估前庭和/或颈部本体感觉输入是否参与头无拘束猴子的FEF和补充眼区(SEF)的视觉运动协调处理(即确定刺激诱发的眼跳的方向)。在特定目标2下，我们将确定前庭和颈部本体感觉输入是否更新了FEF和SEF神经元的运动和/或视觉坐标。这些实验有望为理解大脑皮质对空间坐标的处理带来洞察力，这些发现将对进一步理解总体上运动控制的神经机制具有重要意义。

DESCRIPTION (provided by applicant): Vast amounts of research in the past have shown that the evoked oculomotor vectors reflect the process of visuomotor coordinate transformation. Some recent studies have shown that non-oculomotor variables, such as vestibule and/or neck proprioception, can alter the oculomotor coordinates. Our preliminary studies further indicate that the directions of the neurally evoked saccadic vectors in the frontal eye field (FEF) are shifted in the compensatory direction with respect to changes in static vertical head position. These findings together suggest that the vestibule and/or neck inputs may be critical in updating the visuomotor coordinate frames even if the head is not moving. Based on these findings, we hypothesize that the otoliths, the inner ear organs dedicated to the detection of static head position with respect to gravity, may provide critical inputs to the frontal cortex to help shape the oculomotor coordinates. Alternatively, the neck proprioceptive inputs, which often vary together with the vestibular signals, may be important. To determine whether our findings are contributed solely by vestibular inputs (vestibule hypothesis), neck proprioceptive inputs (neck hypothesis), or both, we have developed a novel approach which permits dissociation of vestibular and neck influences based on independent control of the pertinent movement variables, e.g. initial eye position (IEP), initial head position (IHP), and initial neck position (INP), in head-unrestrained animals. The predictions of the working hypotheses will be evaluated by systematic manipulation of these variables in the proposed experiments. Under Specific Aim 1, we will assess whether vestibular and/or neck proprioceptive inputs participate in the visuomotor coordinate processing (i.e. determining the directions of the stimulation-evoked saccades) in the FEF and supplementary eye field (SEF) of head-unrestrained monkeys. Under Specific Aim 2, we will determine if the vestibular and neck proprioceptive input updates the motor and/or visual coordinates of FEF and SEF neurons. These experiments are expected to bring insights into the understanding of cortical processing of spatial coordinates, and the findings will be important to further the understanding of the neural mechanisms of motor control in general.